Beijing — The deadly race riots now cleaving northwestern Myanmar are an alarming reminder of a key threat to the country’s fragile and embryonic democracy: conflict among Myanmar’s myriad ethnic groups.

Violence continued Tuesday in Arakan state, three days after President Thein Sein declared a state of emergency there and sent troops to quell the looting, arson, and mob clashes that have pitted the Buddhist Rakhine minority against Muslim Rohingya. At least seven people were reported killed.

The president warned in a televised speech that “if we put racial and religious issues at the forefront … if we continue to retaliate and terrorize and kill each other … the country’s stability and peace, democratization process and development … could be severely affected and much would be lost.”

Many ethnic minorities have waged guerrilla insurgencies against the government since Myanmar’s (Burma's) independence in 1948, seeking wider economic and political autonomy from the central authorities, which are dominated by the majority Bamar. The current clashes, however, are different, setting two minorities against each other, and posing an awkward security challenge for the government as it seeks to present a softer and more democratic image, steering the country away from military rule.

Hostility between the Rakhine and the Rohingya dates back many decades; as British troops fell back before the advancing Japanese in 1942, Rakhine mobs took advantage of the power vacuum to launch a pogrom against their neighbors.

The Rakhine regard the Rohingya – descended from laborers imported from what is now Bangladesh by the British colonial government more than a century ago – as foreign intruders. (See map here.)

Deeply oppressed, deeply resentful

The estimated 750,000 Rohingya, one of the most miserable and oppressed minorities in the world, are deeply resentful of their almost complete absence of civil rights in Myanmar.

In 1982, the military junta stripped the Rohingya of their Myanmar citizenship, classing them as illegal immigrants and rendering them stateless. They are not allowed to leave their villages, nor may they marry, without permission. They are forbidden to have more than two children and for many years the authorities have subjected them to slave labor.

“They have been treated in some of the worst ways possible by a government,” says Phil Robertson, deputy director of Human Rights WatchAsia division.

Rohingya make up around 90 percent of the population of north Arakan, but their Rakhine neighbors dismiss them as “Bengali Muslims” and refuse to acknowledge the Rohingya communal identity that local Muslim leaders have forged over the past half century.

“The Rohingya claims to be an ethnic people is a concern to Rakhines because it might lead them to claim territorial rights,” worries Wong Aung, an ethnic Rakhine exile in Thailand who runs an environmental NGO.

For decades, says Mr. Robertson, Myanmar’s military rulers fanned the flames of communal rivalries to divide and rule while tapping into a strain of Bamar racism that has infected many otherwise openminded and liberal intellectuals. “Too many right-thinking people in Burma seem to have been sucked in by the more extreme sort of propaganda,” he says.

Caught between Myanmar and Bangladesh

The Rohingya have suffered a turbulent recent history: Fearing for their safety in the face of military operations in 1978, some 200,000 fled to Bangladesh. Another 250,000 fled in similar circumstances in 1991. Bangladesh, however, has refused to shelter them. This past weekend Bangladeshi coast guard vessels turned away Rohingya boat people as they sought to flee the violence in their homeland.

The Rohingya were allowed to vote in 2010 parliamentary elections that ushered in the new nominally civilian government that has been introducing democratic reforms. But promises of better treatment from candidates of the official Union Solidarity and Development Party have proved hollow.

The new government “has made it very clear in parliamentary statements that [the Rohingya] are a national security problem and that they are not from Burma so they cannot be given rights,” says Chris Lewa, director of the Arakan Project, an advocacy group based in Bangkok.

But the mere fact that a new government has taken office and is introducing political change is bringing old problems to the surface, says Martin Smith, an expert on Myanmar who has studied the country’s ethnic mosaic.

“As the government changes, the lid is opening on old problems that have to be dealt with after so many years of neglect,” Mr. Smith says. “Old problems are going to attract new attention.”

So far, worries Robertson, the government’s refusal to address Rohingya grievances “raises fundamental questions about the government’s ability to forge a peaceful and multiethnic Burma. If they are really reformists,” he argues, “they have to recognize that Burma belongs to all its ethnic groups and races.”